The series of rippling border crossings in response to the migrant crisis and terrorism in Europe has reached all the way to the arctic circle. The AP reports:

Finnish officials say that Russian President Vladimir Putin has agreed to tighten controls at the joint Arctic border for a six-month period, in a move to halt the illegal crossing of migrants.

President Sauli Niinisto’s office says Putin approved measures in Moscow at a meeting of the two leaders Tuesday to limit crossings at the two northern border posts to citizens of Finland, Russia and Belarus, and their families.

The move comes after a surge in asylum-seekers from Russia into northern Finland, raising fears of a new major entry point into Europe for migrants.

More than 1,000 people have applied for asylum at the two Arctic crossings during the first two months of the year — up from less than 700 for the whole of 2015.

Increased crossings in unusual places, and therefore increased border concerns, are to be expected in the wake of the latest Turkey-EU deal struck this Monday. Furthermore, an emphasis on keeping out illegal entries will only grow after the attacks in Brussels on Tuesday. This emphasis will be internal as well as external: the Prime Minister of Poland has already declared, for instance, that it cannot and will not accept any refugees in these circumstances. This will complicate the Turkish deal’s enactment, though by how much, no one can say yet. One thing is for sure, though—the appeal of border restrictionism, internal and external to the EU, is likely to only grow.

What Europe has just done with the Turkey deal is buy itself, at very dear price (an additional €3 billion, Turkish accession talks, a visa scheme that may create immigration trouble down the road for Germany, and serious moral hypocrisy), some time. As critics such as Wolfgang Münchau have rightly pointed out that the demographic pressure to get into Europe right now is so immense that the flow of humanity from a wrecked Middle East and from the failed and failing states of Africa will seek another way—eventually. And the story from Finland emphasizes this. If unchecked, the migrant crisis could well spread to the ends of the Continent, from the Straits of Gibraltar to the Arctic Circle.

But Europe’s nation-states have major organizational, financial, and logistical advantages—if they choose to use them. What the EU must do now is move swiftly to shore up its borders. Greece needs immediate help, from trained personnel to hard cash, to help secure the border. But it can’t stop there: Europe must make sure Spain and Italy are secure, and that they don’t become the next Greece. It must start thinking of the Continent as a whole—of the Finnish-Russian border being connected to the Syrian refugee crisis in the Aegean. And it will have to look abroad to prevent places like Libya from becoming the next Syria.

That’s the kind of proactive policy that would make even this deal worth it; unfortunately, it would also entail the kind of forward thinking and decisiveness that have been so signally lacking so far during this crisis. One thing you can be sure of: if Europe fritters this chance away, the price will be even higher next time.